Electrical ignition control



y 1952 c. COLVIN ELECTRICAL IGNITION CONTROL 2 SHEETS-SHEET 1 Filed Feb. 11, 1950 Fyr. 2

fiTTO/Q/VEY May 13, 1952 c. COLVIN ELECTRICAL IGNITION CONTROL 2 SHEETS--SHEET 2 Filed Feb. 11, 1950 ward flaiwkz INVENTOR I Patented May 13, 1952 ELECTRICAL IGNITION GQN'IRQL Cliii'ord Colvin,

D t oi Mi h? assi nor 3 laims- The ob ect oi his invention s to im ro e he an e. co e-r d he pressure i n t n system of he tre shown n the Gra n N 2-iafi l529 and. the Westcott app tion Seri l No .1 files D cem e 20. 6, now Patent Noasflhfi liissusd Apri 1 9 0. The li itation of the; device shown therein is that it cannot be applied to an engine with overhead valves. Such an engine has so much spark advance that when the high, tension ignition distributor is advanced as fa as, the cam is advanced, it is advanced so far that the sparks no longer register and the ignition becomes irregular and uncertain. In other words, the high tension distributor is so far from the stationary high tension terminal, when the spark is intended to jump, the spark occasionally jumps the wrong way and the engine fires irregularly. In order to solve this problem it was necessary to advance the cam more than the. shaft. This was solved without the. use: oi centrifugal weights by having the cam rotatably mounted on the shaft and by having a. definite degree of travel between theam 5 m. th SttltiQIlfiIy bus i on Wh h th cam is uid d Fricti nal me ns, su h as shown in t e. Mallow expired Patents g. 1,89 4, a e us t a y he timing o hat there are two separat ark advance u e one fo e op n throttle and the oth r for par r t Briefly, the idea of this application is that if you want 41) wide open, throttle and 60 part throttle it cannot be obtained with the present distributor. You have to have 60 travel on the plate to do this. With this distributor you make a plate with travel and get the rest by increasing or decreasing the travel that the vacuum brake gives.

Fig, l is a diagrammatic representation, partially in section, of the carburetor and the ignition timing device associated therewith.

Fig. 2 is. a partial cross-sectional elevation taken on plane 2-2 of Fig. 1.

Fig. 3' is a plan view looking down on the high tension portion of the electrical distributor shown in Fig. e.

Fig. 4 is a cross-sectional plane 41-4 of Fig. 3.

In the figures, I0 is the air entrance. I2 is the venturi. I4 is the fuel nozzle. is is the throttle in the mixture outlet IS. The full lines indicate the. position of the throttle when the engine is runnin idle or when it is not runnin at all and the broken lines indicate the position for ordinarilroad load for maximum spark ad: vanes. 20 is a restriction located upstream of elevation taken on 2 the upstream lip of the butterfly throttle i6 when the throttle I6 is in its idling position. 22 is a vertical passage connecting the restriction 2 3 With the restriction 22. The restriction 24 being located at the point of highest suction in the venturi !.2. A restriction 25 is provided between the passage 22: and the passage 28. Passage 23 connects both the restrictions 29 and 2:1 with the chamber 38., The vacuum tube 32 connects the vacuum in chamber 3!! with the chamber 34. A diaphragm 36 forms the moving wall for the rig-ht hahd wall of the chamber 33. Diaphragm 38. forms a lower moving wall the chamber 34. it is a rod which connects through its right-hand end 42 with the circuit plate M. Two tension springs 45 and i8 anchored to the stationary pins and 52, tend to rotate the plate as in a clockwise direction. These springs are the subject matter of Patent No. 2,503,645. It is noted that the spring 63 is slightly loose on the stationary pin 52 so that when the diaphragm 33 moves to the left the spring as imposes a load, which load is, immediately supplemented by the spring so, as is set forth in the above copending application.

- Pins 54 and 56 are mounted on the plate and constitute the movable anchor pins for the springs and i.-

A drive shaft 58, rotating at half engine speed, rotates plate 68 which engages with a pin 62.

This. pin 62 is free to move in an opening to in the plate 5%. The pin 52 is anchored to the flange disc 55. This flange carries a shaft 958 at: the 81 6.. of which there is a cam is locked ther o- A pin H1 is, mounted on an ear extending from the dri e plate is. he wo p ns 52 n 2 are connected together by tension spring I i. In the position shown the throttle I8 is in the idling position, no suction is applied to chamber 38 or 3 and the brake element it is active. The tension spring Hi in this condition, holds the drive plate 6!}, and; the flanged; disc in the relative position which th y r h wn t the moment the drive shaft 5% begins to rotate the 7 spring; s. is etarded to the re est d ree p ssible. moment the throttle 2i closes the br ke is is released a d he spark; dvanc s.

The usual circuit breaker mechanism is shown and forms no part of this invention. Briefly, there is a pin ildinounted on plate as. There is a breaker arm 2 which has a fiber block as which ides on t e 6am ill. A stationary tungsten point 88 makes and. breaks c ntact with the movin tungsten. point as. Flhe. ignition, of course, is

5/5 controlled whenever this breaks. The whole mechanism is mounted on a plate 90 which is bolted to the plate 44. The usual electrical connections 92 and 94 are provided and the breaker arm 82 is held in engagement with the cam III by means of a steel spring 96. Lock screws 98 and I lock the brake mechanism, just described, onto the plate 44. This constitutes the low tension system which is in universal use today and is no part of this invention.

The shaft I02 acts as a guide for the sleeve 68 Which carries an extension or pilot portion I02. This pilot portion I02 carries a fiat spring I04 (Fig. 4) which engages the high tension arm I06. This arm I06 carries the high tension distributing point I08. High tension entrance cable enters through an opening III]. A conducting spring I I2 conveys the high tension electricity up opening I I6 to the high tension cable, not shown. The high tension cap I I8 carries nine high tension openings. These are as follows: the high tension entrance H0, the high tension exit H6, and the seven other high tension exits I20, I22, I24, I26, I28, I30, and I32.

The ignition device is shown with the throttle in the idling position but with the engine not running. If the engine were running the spring HI- would be stretched and the pins 62 and I2 would be separated by the amount permitted by the opening 64 in the drive plate 60.

Operation It will be noticed in Fig. 3 that with an eight cylinder engine each of the high tension outlets H6, I26, I22, I24, I26, I28, I30, and I32 are separated from each other by an angular displacement of 45.

The distributing point I08 is made of the shape shown in broken lines in Fig. 3. This is shown in two alternative positions and it will be noticed that the full advance of the shaft 58 and the pilot I02 is not large enough to cause the high tension to jump to the wrong set of plugs. By reason of the clearance between the pin 62 and the opening 64 an additional advance is derived from the friction brake I6. Hence, the requirements of an overhead valve engine can be met without disturbing the distribution of high tension electricity.

It will be noticed in Fig. 1 that pin 56 is undercut so that it has to travel inch before it takes up the slack in spring 48.

When running with throttle I6 in position shown in Fig. 1 in broken lines the diaphragm 36 moves over to the left stretching springs 46 and 48 and rotating plate 44 anti-clockwise to advance the spark. At the same time the diaphragm 38 is drawn up releasing the brake I6 fromthe brake drum'66. The effect of this is that, as shown in Fig. 2, spring I4 advances the cam 70 so that the spark is advanced a second time. The high tension distributor arm I06 is driven by the sleeve 68. When the throttle I6 is opened wide then the suction at port 20 is reduced and the Venturi suction at port 24 takes control. Meantime the brake I6 is applied and the brake drum 66 is rotated stretching the spring I4 and retarding the spark. The net result is that the spark is not as advanced as it was when the throttle was only one-half open.

At and below one-half throttle, the spring 14 contracts and rotates the drum 66 at the same time suction at port 20 increases so that the spark is advanced due to two factors, (1) directly by diaphragm 26 and (2) indirectly by diaphragm 38.

What I claim is:

1. In an ignition system for an internal combustion engine having the usual Venturi air inlet and a throttle downstream of the venturi, the ignition system being of the type in which the circuit breaker mechanism is mounted on a yieldably restrained partially rotatable plate and in which there is a movable wall connected to the plate and responsive to the suction in the venturi whenthe throttle is wide open and to the suction downstream of the throttle when the throttle is moved from wide open into a partially open position, said wall acting in opposition to the spring to advance the ignition by rotating the plate, the improvement which comprises an ignition drive shaft, a hollow cam rotatably mounted on the ignition drive shaft and engaging with the breaker mechanism, the ignition drive shaft projecting through the cam, a drive plate rigidly locked in the drive shaft, a driven plate rigidly locked to the hollow cam, spring means normally holding the drive plate and driven plate so as to rotate as one, a friction brake engaging with the rotating edge of the driven plate, a vacuum chamber, a second moving wall associated therewith and connected to the friction brake, a spring acting to oppose the vacuum so as to apply the brake whenever the vacuum falls below some predetermined value, a passage leading from this vacuum chamber to a point downstream of the throttle, a high tension distributor arm mounted on and driven by the projecting extension of said ignition drive shaft, and in which the passage from the vacuum chamber terminates at a point on the atmospheric side of the throttle only when the throttle is in the idling position and this passage is immediately transferred to the suction side of the throttle the moment the throttle is moved slightly away from its idling position.

2. In an ignition system for an internal combustion engine having the usual Venturi air inlet and a throttle downstream of the venturi, the ignition system being of the type in which the circuit breaker mechanism is mounted on a yieldably retrained partially rotatable plate and in which there is a movable wall connected to the plate and responsive to the suction in the venturi when the throttle is wide open and to the suction downstream of the throttle when the throttle is moved from wide open into a partially open position, said wall acting in opposition to the spring to advance the ignition by rotating the plate, the improvement which comprises an ignition drive shaft, a hollow cam rotatably mounted on the ignition drive shaft and engaging with the breaker mechanism, the ignition drive shaft projecting through the cam, a drive plate rigidly locked in the drive shaft, a driven plate rigidly locked to the hollow cam, spring means normally holding the drive plate and driven plate so as to rotate as one, a friction brake engaging with the rotating edge of the driven plate, a vacuum chamber, a second moving wall associated therewith and connected to the friction brake, a spring acting to oppose the vacuum so as to apply the brake whenever the vacuum falls below some predetermined value, a passage leading from this vacuum chamber to a point downstream of the throttle, a high tension distributor arm mounted on and driven by the projecting extension of said ignition drive shaft, and in which the passage leading from the second mentioned vacuum chamber is connected both to the venturi suction and to the suction downstream of the throttle when the throttle is moved from its wide open position.

3. In an ignition timer for an internal combustion engine, a timer shaft, a circuit breaker cam, rotatably mounted thereon, a spring tending to advance the cam relative to said shaft, a driving plate connected to the shaft, a driven plate connected to the cam, said spring formin the driving connection between the two plates, a friction brake acting on the driven plate so as to retard the cam when the brake is applied, a rotatable circuit breaker plate, a circuit breaker arm thereon engaging said cam, a pair of contacts, one on the arm, the other on the circuit breaker plate, a source of engine produced suction responsive to the velocity of air flow entering said engine and to the static suction in the air entrance to said engine, a first diaphragm connected to said circuit breaker plate so a to advance the spark as the said suction increases, a second diaphragm connected so as to release said friction brake as the said suction increases a spring means for opposing each of said diaphragms so as to determine the degree of suction at which the brake is released and the circuit breaker plate is advanced.

CLIFFORD COLVIN.

Name Date Mallory June 12, 1934 Number 

